Hydrostatic pressure type continuous sterilizing and cooling apparatus



Oct 9, 1968 P. CARVALLO HYDROSTATIC PRESSURE TYPE CONTINUOUS STER ANDCOOLING APPARATUS 2 Sheets-Sheet 1 Filed Aug. 5. 1966 51 iil iiri wUnited States Patent 3,407,721 HYDROSTATIC PRESSURE TYPE CONTINUOUSSTERILIZING AND COOLING APPARATUS Pierre Carvallo, Amposta, Tarragone,Spain Filed Aug. 3, 1966, Ser. No. 570,021 Claims priority,appliczaigrlrll rance, Aug. 20, 1965,

9 Claims. (cl. 99-449 ABSTRACT OF THE DISCLOSURE This invention relatesto improvements in hydrostatic pressure type continuous sterilizing andcooling apparatus, particularly for sterilizing preserved foodstuffs,milk, beverages, dietetic and pharmaceutical products and so on.

By their nature most equipment of this kind has great height, andtherefore requires installation in a pit or as an above-ground tower.For the sake of convenience, in tower installations a loading andunloading station is provided at the bottom of the structure.Consequently, a first rising circuit, followed by a conveyor whichstarts from a loading station and goes through the sterilizing enclosurebefore returning to the unloading station, the first circuit preceding adescent in a hydrostatic entry column, is almost completely Wasted inoperation; similarly, only partial use is made of the aforesaid descentin the first hydrostatic pressure column. Associated with this partialuse are inconstant heat conditions, with the result of indeterminateparticipation in the sterilization cycle.

An object of this invention is to obviate these disadvant-ages.

The invention accordingly comprises, in accordance with a firstimprovement, a first rising sectional column of the path followed by aconveyor, such section being closed at its bottom end by a water seal.It then becomes possible to maintain in the section a constant andcontrollable temperature as well as a constant and controllablepressure. Given such temperature constancy conditions, the heat exchangein this section can have a clearly defined participation in the overallsterilizing process.

According to another improvement, the adjacent descending section of theconveyor path, which section can form a pressure-maintaining hydrostaticcolumn of the entry of the sterilizing enclosure, is also maintained atcontrolled temperature conditions, inter alia by heat-conductive contactwith the aforesaid rising section.

In another embodiment/the temperature conditions are maintained throughthe agency of one or more vertical rows of holes at the bottom of thenext pressurized steam column, the bottom level of the Water thereinuncovering a varying number of holes to allow a varying amount of steamto pass through them.

When an apparatus of this kind comprises a pressure steam-heatedsterilizing enclosure, the situation of the aforesaid rising sectionwhich is disposed near the entry can be maintained by steam, so thatsuch apparatus can comprise at least two steam columns with gradedtemperatures.

With this form of heating, and according to another improvement, thepressures and therefore the temperatures of the various sections can becontrolled by the use of a single regulator, preferably of thefloat-controlled steam inlet valve kind, the float following the levelof the water in the hydrostatic pressure columns, preferably at thebottomof the lower-space or lowest-pressure col- -umn-i.e.,substantially in the water seal. With this control, the valve deliverssteam to the hotter or hottest column, excess steam therein going to theless hot or least hot column.

Preferably, the steam inlet orifice in the hotter column is disposed atthe base thereof and the orifice for delivering to the less hot columnis disposed in the upper part thereof.

It a larg number of columns are disposed in series, the distributing andintake orifices are arranged similarly, to ensure automatic air bleedingfrom all the steam columns consecutively, the air bled from the finalcolumn being sent to the drain.

According to another feature, to maintain the top levels of thehydrostatic columns completely constant despite possible irregularitiesin the flow of treated receptacles going through the apparatus, one ormore positive displacement type compensating pumps continuously raisethe excess water 'at the bottom of the columns to accum-ulatorcapacities at the tops of the columns, the latter capacities havingpermanently open overflows to ensure that the top levels stay constant.Preferably, the intake and distribution of this water are effected byspecial compartments disposed at the top of the columns, with regulardistributors over the whole width of the apparatus. These distributingoverflow devices can be double, so as to provide the remainder of theflow ensuring a constant level in any particular hydrostatic column, andalso to provide a trickle without mixing of waters of differenttemperatures in an adjacent steam column.

Advantageously, a heating column is supplied with steam through a singlepermanently open connecting tube, with the use inter alia of a heatseparation which may exist between the system comprising a risingheating column and a descending section or hydrostatic pressure columnand an adjacent system or actual sterilizing ber, thus automaticallyensuring pressure grading and therefore temperature grading betweenthese par-ts of the apparatus.

The following description, together with the accompanying exemplarynon-limitative drawings, will show clearly how the invention can becarried into effect and disclose other advantageous features which ofcourse form part of the invention.

In the drawings:

FIG. 1 is a diagrammatical elevation view in section, with parts brokenaway, of a single-column hydrostatic pressure sterilizing apparatuswhich precedes a sterilizing chamber.

FIG. 2 is a similar view of an apparatus having double pressure columns,and

FIG. 3 is a view of a portion of an alternative heating for ahydrostatic pressure column at the entry of a sterilizing chamber.

As can be seen in FIG. 1, two endless chains C forming part of aconveyor bear baskets P containing receptacles for treatment. The chainsrun over consecutive reversing pulleys or sprocket wheels or the like.Pulley 1 is disposed above a loading and unloading station for thebaskets P and has one side above a bottom reversing pulley 2 which is atthe entry of the apparatus. Other consecutive pulleys 3-9 make thechains C follow a sinuous path along the adjacent vertical columns. Abottom pulley 10 receives the chains from pulley 9 and in turn advancesthe chain at the same level to a final pulley 11 disposed verticallybelow pulley l. The conveyor shown is of the kind comprising tubularbaskets P which are open at their ends and not secured to the chains C,however, the baskets can be of any other known kind and, for instance,comprise baskets rigidly secured to the chains, section members securedto the chains and forming receptacles which open on curves, or any othersystem which, as well as providing the required conveyance, enable theconveying elements to be provided with receptacles for treatment and tohave the receptacles removed from such elements after treatment of thereceptacles.

During the first rise of the chains between the pulleys 2 and 3, thechains are in a hermetic chamber whose bottom part is closed by a waterseal. All the water seals which will be mentioned hereinafter aredesignated in references attached to the two levels which bound theseals. The water seal associated with the pulley 2 is bounded by a toplevel on one side of a partition and by a bottom level 16 on the other.

Downstream of the pulley 3 is a column which is disposed between the toppulley 3 and the bottom pulley 4 and which is filled with water andwhich forms a hydrostatic pressure column bounded at one end by a bottomlevel 19 and at the other end by a top level 22. The receptacles fortreatment are heated in this column before entering a sterilizingchamber, which is in the form of a closed space bounded at the bottom bythe level 19 and disposed between the pulleys 4 and 6, which are at thesame level as one another and below the pulley 5.

Disposed between the pulley 6 and the pulley 7 is a column which is acooling column as well as a hydrostatic pressure column. The followingcolumns, between the pulley 7 and the bottom pulley 8, and then betweenthe pulley 8 and the top pulley 9, are extra cooling columns. A finalcolumn between the pulley 9 and the pulley 10 is a final cooling columnbefore a bottom passage disposed between the pulleys 10 and 11 which areat the same level as one another, the pulley 11 being disposed at thebottom of a return column for receptacles which have been treated at thestation situated where is attached the reference P.

A regulating float is disposed in the water at the level 16 at the waterseal exit and operates a steam inlet valve automatically in accordancewith variations of the level 16, the steam entering the sterilizingchamber through an orifice 18. The opening of the valve tends toincrease when the level 16 rises and to decrease when the level 16drops. The pressure of the inlet steam maintains the level 19 at thebottom of the sterilizing chamber. An exhaust orifice 20 opens into thisregion above the level 19 and communicates through a tube with anorifice 21 with which the chamber receiving the pulley 3 is formed abovethe level 22. The latter tube extends through an insulating spacebetween the hydrostatic column identified by its top level 22 and theactual sterilizing chamber Where the water reaches the level 19.

The surplus steam flowing through the orifice 21 can therefore maintainthe pressure and therefore the temperature constant in the column whichis disposed between the pulleys 2 and 3 and which is bounded by thelevel 16. The top level 22 of the water column extending between thepulleys 3 and 4 is maintained constant by an overflow of water from achamber 23 communicating, via a row of evenly spaced holes 24, with thelatter column; the com partment 23 has an overflow device 25 whichdelivers surplus water, for instance, by trickling, to the water sealbetween the levels 15 and 16. The top level 15 of the latter water sealis maintained constant by the overflow from a chamber 27 via a row ofevenly spaced connecting holes 26; the chamber 27 has an overflow device28 adapted to deliver surplus water to a drain or, if required, to someform of heat recovery device.

The chamber 27 is formed near the bottom with an orifice 29communicating with a positive displacement compensating pump (not shown)delivering to an orifice 30 near the bottom of the chamber 23. Thiswater supply automatically keeps the level 22 constant, moreparticularly in the event of drops due to irregularities, such as aconsiderable drop in the flow of the receptacles contained in theconveyor baskets P during movement of the conveyor C.

The level 33 in the bottom passage where the pulleys 10, 11 are disposedis kept constant by a float valve 31 disposed in an adjacent tank orchamber or the like communicating through orifices 32 with the latterpassage, the orifices 32 being disposed in a row and being evenlydistributed over the whole width of the passage.

The passage is formed below water level with an orifice 34 communicatingwith the intake of a pump (not shown); the delivery thereof comprises abranch through which some of the pump delivery goes to an orifice 35 atthe bottom of an auxiliary chamber 3-6 having at the top an evenlyspaced row of holes 37 communicating with the column which extendsbetween the pulley 9 and the pulley 10. Through the holes 37 water cantrickle in an evenly distributed form on to the products going throughthe column. Another portion of the water delivered by the last-mentionedpump, in a quantity which is preferably thermostatically controlled,goes to a bottom hole 38 of another auxiliary chamber 39 adjacent thecolumn extending between the pulleys 8 and 9. The chamber 39 is formedwith a number of holes 40 communicating with the column between thepulleys 8 and 9. The water flowing through the holes 40 descends in thelatter column but rises in the column between the pulleys 7 and 8, thenenters the column between the pulleys 6 and 7 through a row of holes 41which are evenly spaced in a line and which are in a separatingpartition between these tWo adjacent columns. Below the level 19 thisfiow of water rises in the column between the pulleys 3 and 4 and isfinally removed through the holes 24 and overflow device 25, then goesthrough the holes 26 and overflow 28 either to a drain or to heatrecovery.

Consequently, the water which is first used for cooling in the passagebetween the pulleys 11 and 10 flows in a complete circuit incountercurrent to the conveyor (except for the trickling in the columnbetween the pulleys 9 and 10), and is then heated by heat recovery; theheat recovered during cooling in the output columns of the sterilizingchamber and in the extra cooling columns is used to heat the productsfor treatment between the levels 19 and 22.

Depending upon the height of the water column between the levels 19 and22, the pressure and therefore the temperature in the sterilizingchamber-ie, in the passage bounded by the pulleys 46is kept constant,for instance, about 120 C., by steam injection through the hole 18. Thewater seal between the levels 15 and 16 keeps the pressure and thereforethe temperature constant-e.g. at 101 C.in the column between the pulleys2 and 3. Consequently, the water of the adjacent column is alsomaintained at this constant temperature of 101 C. by contact with theaforesaid steam column between the pulleys 2 and 3 and possibly by thebubbling of a steam injection through a nozzle 42 at the bottom of thecolumn between the pulleys 3 and 4.

As can be seen in FIG. 3, instead of a nozzle 42, the bottom of thecolumn between the pulleys 3 and 4 could be formed with a number ofholes 42a preferably arranged in parallel vertical rows, to provideautomatic super.- vision, according to the position of the level 19, ofthe amount of steam bubbling into the column between the pulleys 3 and4. In this system, the passage 20 is normally omitted and the pressurecolumn between the pulleys 3 and 4 is automatically maintained at agraded temperature going, for instance, from C. at the bottom to C. atthe top of the column where the water, which enters boiling, suppliessteam to the column which extends between the pulleys 2 and 3;consequently, the bottom level 16 of the latter column controls automatically, and via a single regulator, the three columns which extendbetween the pulleys 2, 3 and 3, 4 and 4, 5, 6 respectively, equilibriumbeing achieved through the agency of the level 19 which uncovers avarying number of holes 42a.

If required, both procedures can be combined, in which event the passage20 is controlled by an adjustable valve.

The dwell time in the steam column between the pulleys 2 and 3 and inthe water column between the'pulleys 3 and 4 at an appropriatelycontrolled temperature can therefore be taken into account indetermining the total sterilization time of the products being treated.

Another advantage of using a water seal as the bottom closure for thecolumn between the pulleys 2 and 3 is that a stream of water at apredetermined temperature can be provided inside the latter column ifrequired, for instance; for low-temperature pasteurization.

FIG. 2 shows a variant of a similar apparatus but having a doubleloading station P and having double hydrostatic pressure columns. Toenable higher temperatures to be maintained with a reduced overallheight, the columns between the levels 19b and 22a and between thelevels 19b and 22b, in order to have additive elfects, maintain arelatively high total pressure in a high-pressure sterilizing chamberthrough which the conveyor C runs over pulleys, sprockets or the like6a, 7a, 8a similar to those described with reference to FIG. 1 andhaving the same references as in FIG. 1 plus the index a.

A float regulator 17a controls the entry of steam into this chamberthrough a nozzle 18a, and the excess steam goes consecutively throughorifices 20a, 21a, as in the sterilizing chamber of the firstembodiment, to the first hydrostatic pressure column, then throughorifices 20b, 21b therein to the second such column, under the sameconditions as in FIG. 1, the separating walls or partitions between thehydrostatic columns and the sterilizing chamber being in all cases farenough apart and adequately insulated. Similarly, the constancy andgrading of the temperatures between the columns of the sterilizingchamber are maintained automatically, the sterilizing chamber (pulleys6a, 7a, 8a) being at atemperature, for instance, of 125 C., whereas thetemperature in the columns 4a, 5a is 115 C. and in the columns 2a, 3a isonly 101 C. As in the previous embodiment and as shown in FIG. 3, theorifices 20a, 20b can be replaced or supplemented by vertical rows ofholes 42a, in which event the single regulator 17a can control thetemperatures in the three steam columns (6a, 7a), (4a, 5a) and (2a, 3a)and in the two pressure columns (5a, 6a) and (3a, 4a). The pressure inan intermediate cooling column disposed between the pulleys 9a and a ismaintained by compressed air supplied from a bank or battery 43 in turnsupplied by a compressor (not shown); a connecting joint 44 equalizesthe pressures as between the chamber between the pulleys 4a, 5a and thechamber between the pulleys 9a and 10a.

Via an orifice 46 immersed in the liquid at the bottom of the columnbetween the pulleys 9a and 10a, the cooling water is taken up by a pump(not shown) and distributed directly to a chamber 36a at the top of thelatter column, the latter chamber being formed with orifices 37a viawhich water can trickle on to the products descending therein. Some ofthe delivery of the latter pump, the exact amount being controlled by athermostat, goes to an adjacent chamber 390 formed with orifices 40a tomaintain the level in the column which is passed through between thepulleys 8a and 9a and which is the first pressure-maintaining column.

Via an immersed orifice 34a in the last column extending between thepulleys 11a and 12a, another pump takes up the Water and delivers itthrough an entry 48 to a chamber 47 formed with a single horizontal rowof orifices 49 serving to keep the level constant in the columnextending between the pulleys 10a and 11a and an overflow tricklethrough orifices 50 on the opposite side which open at the top of thecolumn between the pulleys 11a and 12a. As will be apparent, the chamber47 is so devised that the cool water arriving via the entry 48 maintainsthe level in the second pressure column 10a, 11a by a make-up of coolwater distributed over the whole width of the conveyor, but the excesstrickling through the orifices 50 over the whole width of the conveyordoes not mix with the warm water in the column 10a, 11a. This is animportant feature for satisfactory grading of the cooling temperatures,particularly for treating glass receptacles.

As in the case shown in FIG. 1, a compensating positive displacementpump (not shown) is adapted to take up water from the reserve chamber27a through the orifice "29a and to deliver such water to the inlets30a, 30b in two chambers 20a, 23b which keep the levels 22a, 22bconstant despite possible variations in the loading of the conveyor CThe embodiments hereinbefore described can of course be modified withoutdeparting from the scope of the invention. More particularly, the numberand arrangement of the circuits of the progressive pressure stations ofthe extra cooling of sterilizing columns can be other than specified.Similarly, the kind of conveyor used and, consequentially, the devisingof the single or multiple loading and unloading stations, can be otherthan specified. The heating steam can be bubbled through at the bottomof each entry column with any means, with or without control of steamflow by the levels.

What I claim is:

1. A sterilizing and cooling apparatus comprising a conveyor travelingalong a closed path between a loading station for products to be treatedand an unloading station for removal of treated products, a vesselthrough which said conveyor passes for the treatment of said products,said vessel including a sterilizing chamber adapted to contain steam, atleast two hydrostatic pressure columns containing a liquid, at least oneeach on the upstream and downstream sides of said chamber, said vesselincluding a bottom portion and an elevated portion extending above thebottom portion, said loading and unloading stations being located at thelevel of said bottom portion, said conveyor having at least a firsttravel section extending between said loading station immediately in thevicinity of said bottom portion and an inlet of the first upstreamhydrostatic pressure column at the topthereof, an entry column receivingsaid first travel section of the conveyor, said entry column being onthe upstream side of said steam chamber, said entry column having aliquid seal at the lower end thereof, said conveyor passing insuccession through said seal, said entry column, along an ascending paththen through each of said upstream hydrostatic pressure columns, andthereafter through said steam sterilizing chamber and each of saiddownstream hydrostatic pressure columns, and means for the passage ofsteam from said steam sterilizing chamber to said entry column forregulating the temperature in said entry column and maintainingcontrolled temperature conditions in the adjacent hydrostatic pressurecolumn which is in heat conductive relation with said entry column.

2. A sterilizing and cooling apparatus comprising a conveyor travelingalong a closed path between a loading station for products to be treatedand an unloading station for removal of treated products, a vesselthrough which the conveyor passes for the treatment of the products,said vessel including a sterilizing chamber adapted to contain steam, atleast two hydrostatic pressure columns contain ing a liquid, at leastone each on the upstream and downstream sides of said chamber, and anentry column between the loading station and the first hydrostaticpressure column on the upstream side of the steam chamber, the entrycolumn having a liquid seal at the lower end thereof, the conveyorpassing in succession through said entry column, along an ascendingpath, then through each of the upstream hydrostatic pressure columns,and thereafter through the sterilizing chamber and each of thedownstream hydrostatic pressure columns, means defining a passagewaybetween the sterilizing chamber and one of the upstream pressure columnsat the lower end thereof to permit upward flow of steam through theliquid in the latter pressure column and thereby control the temperaturetherein, and means for the passage of steam from the sterilizing chamberto the entry column for regulating the temperature in the entry columnand maintaining controlled temperature conditions in the adjacenthydrostatic pressure column which is in heat conductive relation withthe entry column.

3. Apparatus as claimed in claim 2, wherein said conveyor includes afirst travel section extending between the loading station and the inletto the first pressure column on the upstream side of the chamber, saidfirst travel section being disposed for its greatest part in said entrycolumn.

4. Apparatus as claimed in claim 3, wherein said passageway between thesterilizing chamber and said one upstream pressure column is constitutedby at least one vertical row of holes disposed at the bottom of apartition dividing the chamber and said one upstream column, such thatthe quantity of steam which passes varies with the level of the liquidat the base of said hydrostatic pressure column.

5. Apparatus as claimed in claim 3, comprising a steam inlet duct and asteam outlet duct in said sterilizing chamber, said steam outlet ductbeing connected to the entry column whereby when the chamber is heatedby steam under pressure, a part of said steam is passed through saidoutlet duct into said entry column.

6. Apparatus as claimed in claim 3, comprising a steam inlet duct at thetop of the sterilizing chamber, a steam outlet duct at the bottom ofsaid chamber, in the vicinity of the normal liquid level in saidchamber, said steam outlet duct communicating with the adjacent upstreamhydrostatic pressure column, so that, upon pressure decrease in saidchamber, the steam outlet duct is progressively closed by ascension ofthe liquid level, thus causing a pressure reduction in said entrycolumn, whereby the liquid level at the base of said entry column israised, a float regulator in said liquid at the base of said entrycolumn for increasing the steam input in said chamber when the float iselevated, whereby increase of the liquid level in said chambercorresponds to an opening of the 8 steam inlet in said chamber,resulting in stabilization of pressure in said chamber.

7. Apparatus as claimed in claim 6, comprising a duct connected to thesteam outlet duct in said chamber for conveying steam to the upper partof an adjacent upstream column.

8. Apparatus as claimed in claim 6, comprising a steam outlet at thebase of an intermediate hydrostatic pressure column, in the vicinity ofthe lower liquid level in said column, a duct connected to the lattersaid steam outlet, and to a steam inlet in an upstream adjacent column,the latter steam inlet being located above the upper liquid level insaid adjacent upstream column.

9. Apparatus as claimed in claim 3, wherein the downstream liquidhydrostatic columns constitute cooling columns, the apparatus furthercomprising a first cooling column located on the downstream side of thelast downstream liquid column and a second cooling column located on theupstream side of said last downstream liquid column, and means forsupplying said first and second cooling columns with a cooling liquidfor descending flow therein, an overflow chamber 'at the top of saidfirst cooling column, said overflow chamber being supplied with liquidfrom the bottom of said first cooling column, said overflow chamberhaving an outlet at a particular level opening into the last downstreamliquid column to furnish cooling liquid thereto to maintain a constantlevel in said last liquid column, said chamber having a further outletat a higher level than the first outlet and opening into the firstcooling column for the supply thereinto of cooling liquid in the form ofa trickle.

References Cited UNITED STATES PATENTS 1,419,139 6/1922 Hunter 993621,584,397 5/1926 Paxton 99-362 X FOREIGN PATENTS 448,693 7/ 1936 GreatBritain. 648,345 1/ 1951 Great Britain. 730,781 7/ 1955 Great Britain.731,550 7/1955 Great Britain.

WALTER A. SCHEEL, Primary Examiner.

J. M. NEARY, Assistant Examiner.

